To determine the correct description, we analyze the magnetic behavior of each oxygen species based on the number of unpaired electrons in their electronic configurations:
- O2 (Dioxygen): Has 16 electrons. Its molecular orbital configuration ends in (π∗2px1=π∗2py1), meaning it has two unpaired electrons and is paramagnetic .
- O2+: Has 15 electrons. It is formed by removing one electron from a π∗ orbital of O2, leaving one unpaired electron. Thus, it is paramagnetic.
- O2− (Superoxide): Has 17 electrons. It has one additional electron in the π∗ orbitals compared to O2, leaving one unpaired electron. Thus, it is paramagnetic.
- O22− (Peroxide): Has 18 electrons. Both π∗ orbitals are fully occupied (π∗2px2=π∗2py2), meaning all electrons are paired. Thus, it is diamagnetic.
- O (Oxygen atom): Has 8 electrons. Its atomic configuration is 1s22s22p4. According to Hund's rule, it has two unpaired electrons in the 2p orbitals and is paramagnetic.
- O+ (Oxygen atom cation): Has 7 electrons. Its configuration is 1s22s22p3, with three unpaired electrons in the 2p orbitals, making it paramagnetic.
Evaluating the options: Option A is incorrect because O22− is diamagnetic. Option B is incorrect because O2− is paramagnetic. Option C is incorrect because O22− is diamagnetic. Option D is correct because both O2+ and O2 are paramagnetic.